async function async1() {
    console.log('async1 start');
    await new Promise(resolve => {
        console.log('promise1')
    })
    console.log('async1 success');
    return 'async1 end';
};


console.log('script start');

async1().then(res => console.log(res));

console.log('script end');

// script start -> async1 start -> promise1 -> script end


// await 后面的promise一直没有改变状态后面就不会再响应了